High exhaust temp alarm

[davidr]

Got a high exhaust temp alarm on 435 hp D6. Engine temp was normal 185. Looking at the CB30 owners manual, I see a sea strainer for the raw water wash down…my boat is plumbed to use fresh water to flush the head. Is there a separate strainer for engine? Any trouble shooting tips would be appreciated!

 

[BB marine]

Strainers used on a C30

Head/raw water wash down strainer

Marine Air strainer

Engine raw water cooling strainer

Inspect the engine strainer for fouling. Clean if needed. How many hours and years on the engine raw water cooling pump impeller?

In some cases the exhaust temp increases because of excessive engine loading. What is the Max WOT rpm ? It should be turning 3500 rpm +150/-100. If the bottom is dirty, loaded heavy, fouled prop, or damaged prop the engine may be operating over propped this will increase exhaust temp.

 

[davidr]

Impeller was just changed over the winter plus new bottom paint. I checked WOT and was pulling 3450 rpm with no tweaking of trim. Was on the first ride of the year bringing her home from winter moorage running st about 2000 rpm when I got the alarm.
There was a lot of junk in the water today (San Juan Islands, WA) and I suspect I picked up some bull kelp. Will do some more investigation in the next day or so…Need to spend some time with the engine hatch open checking strainer locations. May also have a diver check it from below.

 

[dbsea]

Your raw water strainer for the engine is on the port side of the engine compartment, mounted on the floor. Can’t miss it. Giant brass thing with large hoses. Close the seacock and remove the filter and clean it.

 

[davidr]

Had a diver go under the boat today. There was a remnant of a stick between the prop and skeg. Small mark on one blade
tip but everything else was fine. Another one for the book of boat knowledge. Will probably replace prop at next haul out.

 

[nzfisher]

You can have the pro pulled and checked by a prop house before you pop for a new prop. A good mechanic house will have a recommendation.